Resonant DC to DC converters are considered to be attractive power conversion solutions for the many benefits they can provide. Following a resonant tank with transformers provides galvanic isolation which is important for level conversion as well as for safety. In certain applications, galvanic isolation is required for proper operation. Resonant converters also have inherent properties, such as soft switching of the semiconductor switches, which lead to high efficiency and low noise.
The developing trends of the isolated DC-DC converters are very high efficient, high power density and low cost. The resonant DC-DC converters are suitable technology to achieve high efficiency in power converters due to the intrinsic capability to achieve soft switching (i.e., zero voltage switching (ZVS) and zero current switching (ZCS)). It is also possible to increase the switching frequencies in order to reduce the size of the reactive components of the system.
However, there are still drawbacks regarding the conventional three-phase resonant converter operating at high frequency (HF). Galvanic isolation in three-phase converters poses challenges in the construction and the connection types of the three-phase resonant converter. The common transformer and transformer connections types for the three-phase resonant converter are three winding transformers. The cost of this existing technology increases with attempts at higher efficiency and reduced volume and weight.
Accordingly, it would be desirable to provide a DC-DC converter topology that addresses at least some of the problems identified above.